Cosmetic work on birther screen.

Remove extra spaces at the beginning of race descriptions and c_tut text.

Make Reroll and Reset buttons the same width.

Increase vertical spacing between a few controls.

Move Play / Load / Cancel buttons' initializations up so I can access their
size sooner.

Race / class / background / alignment lists now dynamically size based on
screen size.
Implement right-click to reduce stats.  Fix point buy.

Point buy values were calculated incorrectly; Pathfinder's numbers are a
total, not a delta.  This made increasing stats cost far too much.

Make reroll an instance variable for better coding style.

Reduce points for point buy from 32 (way beyond epic fantasy) to 20 ("high
fantasy").  Would 15 ("standard fantasy") be better?
Minor cleanup - remove unused "delta"
Merge pull request #140 from joshkel/birther-work

Birther work